Assembly Secretary K. Boopathy said that after the disqualification under the Tamil Nadu Legislative Assembly (Disqualification on Ground of Defection) Rules 1986, the 18 ceased to be MLAs from Monday.

With this, the effective strength of the 234-member House (where late Chief Minister J. Jayalalithaa’s seat remains vacant) has come down to 215. And against a half-way mark of 109, the Chief Minister claims to enjoy the support of 114 MLAs.

Though notices were issued by the Speaker initially to 19 AIADMK MLAs who took sides with Dinakaran, one of them, S.T.K. Jakkaiyan, shifted his loyalty to the Chief Minister.

The 18 MLAs have neither quit their party membership nor joined another political party, grounds on which an MLA can be disqualified.

Reacting to the development, Dinakaran told reporters that they would file a case against the Speaker’s action. “Justice will triumph. Betrayal will never win.”

His loyalist MLA Thanga Tamilselvan said in Kodagu in Karnataka, where the MLAs are staying in a resort, that they were 100 per cent confident that they would get justice in courts.

They would not rest till the Chief Minister was removed, he said.

Last week, senior lawyer Kapil Sibal, who appeared for the DMK on a petition seeking an immediate floor test in the Assembly, told the Madras High Court that he feared the Speaker could disqualify these MLAs and conduct a floor test to facilitate Palaniswami to prove his legislative majority.

The opposition parties have been demanding that the government should prove its majority on the floor of the house after 19 legislators asked the Governor to initiate the process to install a new Chief Minister.

DMK leader M.K. Stalin told the media on Monday that the Speaker’s action amounted to “cruel murder” of democracy and was an attempt by the Chief Minister to take a short cut to prove his majority in the Assembly.

The decision was a result of the “collaboration” between the Speaker and the Chief Minister, he said.

The Madras High Court had ordered that a floor test should not be held till September 20 for Palaniswami to prove his legislative majority.

Stalin had claimed earlier that the Palaniswami government has lost majority support after the legislators belonging to Dinakaran group withdrew their support to Palaniswami.